proteases

(noun)

A class of enzymes that can cleave proteins.

Related Terms

Examples of proteases in the following topics:

  • Protease Inhibitors

    • Protease inhibitors target viral proteases which are key enzymes for the completion of viral maturation.
    • Proteases are enzymes that have the ability to cut proteins into peptides.
    • Natural protease inhibitors are found in Shiitake mushrooms.
    • Some protease inhibitors do not mimic peptides in their structure.
    • It is one of the major drawbacks of protease inhibitors therapy.

  • Proteolytic Degradation

    • Polypeptides are commonly broken down via hydrolysis of the peptide bonds by utilizing a class of enzymes called proteases.
    • The lysosome contains proteases that are able to target and degrade proteins.

  • Replicative Cycle of HIV

    • There, it is cleaved by HIV protease and processed into the two HIV envelope glycoproteins, gp41 and gp120.
    • During maturation, HIV proteases cleave the polyproteins into individual functional HIV proteins.
    • This cleavage step can be inhibited by protease inhibitors.
    • Steps in the HIV Replication Cycle: Fusion of the HIV cell to the host cell surface.Cell Entry, HIV RNA, reverse transcriptase, integrase, and other viral proteins enter the host cell.Viral DNA is formed by reverse transcription.Viral DNA is transported across the nucleus and integrates into the host DNA.New viral RNA is used as genomic RNA to make viral proteins.New viral RNA and proteins move to cell surface and a new, immature, HIV virus forms.Virus maturation and protease release of individual HIV proteins.

  • Enzymes Used in Industry

    • Proteases are used by biscuit manufacturers to lower the protein level of flour.
    • Amylase, glucanases, and proteases are used to split polysaccharides and proteins in the malt.
    • Proteases are used to remove cloudiness produced during storage of beers.
    • In the production of biological detergents, proteases, produced in an extracellular form from bacteria, are used in pre-soak conditions and direct liquid applications, helping with the removal of protein stains from clothes.

  • Paralysis-Causing Bacterial Neurotoxins

    • This light chain is an enzyme (a protease) that attacks one of the fusion proteins (SNAP-25, syntaxin or synaptobrevin) at a neuromuscular junction, preventing vesicles from anchoring to the membrane to release acetylcholine.
    • The light chain of the toxin has protease activity.

  • HIV Attachment and Host Cell Entry

    • After HIV has bound to the target cell, the HIV RNA and various enzymes (including reverse transcriptase, integrase, ribonuclease, and protease) are injected into the cell.
    • Steps in the HIV Replication Cycle: Fusion of the HIV cell to the host cell surface.Cell Entry, HIV RNA, reverse transcriptase, integrase, and other viral proteins enter the host cell.Viral DNA is formed by reverse transcription.Viral DNA is transported across the nucleus and integrates into the host DNA.New viral RNA is used as genomic RNA to make viral proteins.New viral RNA and proteins move to cell surface and a new, immature, HIV virus forms.Virus maturation and protease release of individual HIV proteins.

  • Two-Hybrid Analysis

    • In addition to being fused to an integral membrane protein, the Cub moiety is also fused to a transcription factor (TF) that can be cleaved off by ubiquitin specific proteases.
    • The reconstituted split-ubiquitin molecule is recognized by ubiquitin specific proteases, which cleave off the reporter protein, allowing it to induce the transcription of reporter genes.

  • Role of the Complement System in Immunity

    • When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages.
    • C1 acts a protease and cleaves C2 and C4 to form C4b2b.
    • Proteases bound on the other side of the MBL cleaves C4 into C4a and C4b.

  • Coagulation

    • The coagulation factors are generally serine proteases (enzymes).
    • Protein C: a vitamin K-dependent serine protease enzyme that degrades Factor V and factor VIII.
    • Antithrombin: a serine protease inhibitor that degrades thrombin, Factor IXa, Factor Xa, Factor XIa, and Factor XIIa.

  • Secondary & Tertiary Structure of Large Peptides and Proteins

    • Examples of proteins having a quaternary (or quartary) structure include hemoglobin, HIV-1 protease and the insulin hexamer.
    • HIV-1 protease is an enzyme made by the HIV virus that is essential for it's life-cycle.
    • HIV-1 protease cleaves the nascent proteins into their functional form.
    • Without effective HIV-1 protease, HIV virions remain uninfectious.
    • Because of its role in HIV replication, HIV-1 protease has been a target for antiviral drugs.